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On 19th Jan 2008, at about 1900 at ship in DR 00˚ 02’N 170˚ 50’E, the sextant altitude of the star BETELGUESE was 43˚ 11.1’ at 07h 33m 44s by GPS clock. If IE was 1.3’ off the arc & HE was 18m, find the direction of the LOP and the intercept.
d h m s
GMT 19 07 33 44
LIT (E) (+) 11 23 20
LMT 19 18 57 04
GMT 19 Jan 07h 33m 44s
GHA Ȣ(19d 07h) 223˚ 03.7’ Dec N 07˚ 24.6’
Incr. (33m 44s) 008˚ 27.4’ Lat 00˚ 02’ N
GHA Ȣ 231˚ 31.1’
SHA * (+) 271˚ 05.4’
GHA * 142˚ 36.5’
Long (E) (+) 170˚ 50.0’
LHA * 313˚ 26.5’
P = (360˚ – LHA)
= (46˚ 33.5’)
We know that :
Cos CZD = ( Cos P × Cos Dec × Cos Lat) + ( Sin Lat × Sin Dec )
Cos CZD = ( Cos 46˚ 33.5’ × Cos 07˚ 24.6’ × Cos 00˚ 02’ ) + ( Sin 00˚ 02’ × Sin 07˚ 24.6’ )
CZD = 47˚ 00.2’
Sext Alt 43˚ 11.1’
IE (OFF) (+) 01.3’
Observed Alt 43˚ 12.4’
Dip (HE 18m) (-) 07.5’
App Alt 43˚ 04.9’
T Corrn. (-)01.0’
T Alt 43˚ 03.9’
TZD 46˚ 56.1’
TZD = 46˚ 56.1’
CZD = 47˚ 00.2’
Intercept = 04.1’ TOWARDS
Azimuth = N 79.9˚ E
T Az = 079.9˚ (T)
LOP = 169.9˚ – 349.9˚
